In general, a stabilizer control apparatus for a vehicle is adapted to apply an appropriate roll moment to the vehicle from outside thereof according to an action of a stabilizer, while the vehicle is traveling with a turning operation, to reduce or restrain a rolling motion of a vehicle body. In order to achieve this function, in Non-Patent document 1 as cited hereinafter, for example, a system called “Dynamic Drive” has been proposed to stabilize the rolling motion of the vehicle actively by making use of hydraulic pressure. That is, a tandem pump actuated by an engine is used as a power source, and sensor signals • CAN signal are input, so that a lateral kinetic signal is determined on the basis of logical or mathematical combination of those signals. On the basis of those signals, a proportional pressure control valve for setting an active pressure and a directional control valve for ensuring the direction of oil are controlled. Two pressure sensors for front and rear axle stabilizers are provided in a valve block, and the detected pressures are fed back to a control unit, in the same manner as the direction control valve.
Also, there is known an active roll restraining control apparatus using an electric system. For example, in Patent document 1, proposed is an apparatus for controlling efficiency of a stabilizer to vary an apparent torsional rigidity of the stabilizer by driving and controlling an actuator in response to a turning level of a vehicle. In practice, it is so constituted that driving force of an electromagnetic linear actuator is calculated on the basis of signals of various sensors, and converted into electric value to provide a desired electric value for performing a PID control. And, it is described that the actuator is actuated to enlarge or shorten the stabilizer, so as to provide an appropriate torsional rigidity for it, by feeding exciting current to a stator having laminated plates with coils connected together in a three-phase delta circuit, in response to a synchronous signal based on the output of position detecting means, and feeding actual current back to it.
Furthermore, in Patent document 2, there is proposed a side roll stabilizing apparatus provided with the stabilizer bars divided into two portions and an electromechanical slewing actuator arranged between halves of the stabilizer bars. That is, in the Patent document 2, the electromechanical slewing actuator which is used for creating an initial stress torque, is constituted by three basic components, namely an electric motor, a step-down gear and a brake disposed between them. The torque generated by the electric motor is converted by the step-down gear into the torque needed for the initial stress of the stabilizer. One stabilizer half is supported directly by the electromechanical slewing actuator or housing via a bearing mount, and the other stabilizer half is connected to the output end (high torque end) of the step-down gear and is mounted in the bearing mount.    Patent document 1:    Japanese Patent Laid-open Publication No.2000-71739    Patent document 2:    Japanese Patent Laid-open Publication No.2002-518245    Non-Patent document 1:    Dynamic Drive. Technology. [online]. BMW Group, 2002.    [retrieved on 2003-12-08]. Retrieved from the Internet: <URL:http://www.bmwgroup.com/e/0—0_www_bmwgroup_com/713 innovation/7—3_technologie/7—3—4_dynamic_drive.shtml>